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PART I. PLANT LIFE 



EXERCISE 1 



THE BEGINNING OF GROWTH 



Statement. Every live seed contains a plantlet which, under proper conditions, will grow. The 

 early growth of a plant is usually more rapid than that of any subsequent period. A few days in 

 the early period witnesses a remarkable change in the development of all parts of 

 a seedling. 



Object. To discover the way in which growth begins and the conditions which 

 are most favorable for the development of the young plant. 



Materials. Seeds of corn, wheat, peas, and lima beans that will germinate ; 

 dinner plates ; blotters ; flowerpots or tin cans ; and clay subsoil. 



Directions, (i) Place seeds that are alive and those that are dead between 

 blotters in a dinner plate ; moisten the blotters with water and set in a cold 

 place. In like manner prepare three other plates of seeds but omit water from 

 one of them. Place one to which water has been added and one to which no water 

 has been added in a warm, light place. Set the other plate of seeds in a warm, 

 dark place. Keep all moist as needed except the one to which no water was 

 previously added. Compare results each day for a week. 



Make outline drawings of the seeds of peas, beans, and wheat that germinated, 

 showing changes from day to day. Label the parts, root, stem, and leaf, and 

 number them in order of their appearance. 



(2) Fill two flowerpots or cans with finely screened clay subsoil and add water 

 to one of the pots. Stir the soil which has been moistened until it becomes a 

 thick, smooth batter. Plant seeds in each of the two pots and water both alike. 

 Explain the difference in the early growth of the seeds. What does one have 

 which the other lacks? 



(3) Boil some water in a small glass vessel and set it aside to cool. As soon 

 as it comes to room temperature drop in a few kernels of corn or beans. Cover 

 the surface of the water with a thin film of kerosene or motor oil to exclude the 

 air. In another vessel of unboiled water place a similar number of seeds and 

 shake the water in this vessel at least twice a day for ten days. What are the 

 results? Explain them. 



Questions. What happens when seeds lack air? What happens when they 

 lack moisture? Heat? Light? What are the conditions necessary for germina- 

 tion? Which part of the seedling appeared first? Which last? Is the vitality 

 of seeds affected by their age? What is the effect of freezing upon the vitality 

 of unmature seeds? upon mature seeds that are not dry? upon dry mature seeds? 



Fig. 1. The beginning 



of growth in the com 



plant 



References. Waters, H. J. Essentials of Agriculture, pp. 36-37. Ginn and Company. Stoddart, C. W. 

 The Chemistry of Agriculture, pp. 17-21. Lea & Febiger. Hunt and Burkett. Soils and Crops, pp. 185-186. 

 Orange Judd Company. 



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